This application claims the priority of Korean Patent Application No. 2004-55096, filed on Jul. 15, 2004, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present invention relates to a semiconductor device and a method of manufacturing the same, and more particularly, to a 2-terminal semiconductor device that uses an abrupt metal-insulator transition (MIT) semiconductor material and a method of manufacturing the same.
2. Description of the Related Art
Recently, a memory device using a structural phase transition material has drawn interest and research and development regarding this memory device has been actively performed. An example of the memory device using a structural phase material has been disclosed in U.S. Pat. No. 5,687,112. The memory device disclosed is a phase change memory (PCM) device that uses a crystalline phase and an amorphous phase occurring at a high temperature. This device can be used as a memory device since it can use a phase change according to the structural phase transition. However, the device cannot be used for other applications, such as a switching device, because a rapid switching speed cannot be implemented due to the location change of atoms according to the structural phase transition. If a rapid switching speed is forced, the memory device may break due to a hysteresis phenomenon. A drawback of the phase change memory device is its limited applications.
On the other hand, a consecutive metal-insulator transistor, that is, a Mott-Hubbard field transistor which uses a Mott-Hubbard insulator in an insulator that allows a second transition has been suggested as a semiconductor device that uses a metal-insulator transition. The Mott-Hubbard field transistor has been disclosed by D. M. Newns, J. A. Misewich, C. C. Tsuei, A. Gupta, B. A. Scott, A. Schrott, in Appl. Phys. Lett. 73 (1998) 780. The Mott-Hubbard field transistor performs an ON/OFF operation according to the metal-insulator transition. Unlike the conventional MOS field transistor, the integration density of this transistor can be significantly improved since a depletion layer does not exist. Also, the Mott-Hubbard field transistor has higher speed switching characteristic than the MOS field transistor. However, charges to be used for carriers must be added until the Mott-Hubbard field transistor reaches the characteristic of a metal since Mott-Hubbard field transistor uses MIT that is consecutively generated. Accordingly, the charges added must have high concentration, and a dielectric constant of a gate insulating layer must be high, the thickness of the gate insulating layer must be thin, and a gate voltage applied must be greater than the high concentration of the added charge. However, if the dielectric constant is too high, the lifetime of the transistor is reduced since the fatigue characteristic of the dielectric may go badly at a high switching speed. There is a process limit to make a thin insulator. Also, when the gate voltage is high, there is a drawback of high power consumption.
To solve these problems, a switching field transistor that uses an abrupt MIT semiconductor material, not a consecutive transition, has been disclosed in U.S. Pat. No. 6,624,463. The abrupt MIT semiconductor material has a characteristic in that a transition from an insulator to a metal takes place rapidly not consecutively by adding a low concentration of holes to a Mott-Brinkman-Rice insulator. The Hole-driven metal-insulatr transition theory has been disclosed in the article “New Trends in Superconductivity” by Hyun-Tak Kim published in NATO Science Series Vol II/67 (Kluwer, 2002) pp. 137 and at the web address http://xxx.lanl.gow/abs/cond-mat/0110112. Hyun-Tak Kim, Byung-Gyu Chae, Doo-Hyeb Youn, Sung-Lyul Maeng, Gyungock Kim, Kwang-Yong Kang, and Yong-Sik Lim in New Journal of Physics 6 (2004) 52 has also disclosed a research about the abrupt MIT by using vanadium dioxide (VO2) which is a representative Mott-Brinkman-Rice insulator. The problems of the field transistor using the consecutive metal-insulator transition material are solved in the switching field transistor since the concentration of the holes added is very low. However, the availability of the abrupt MIT semiconductor materials is limited and the cost of forming an abrupt MIT semiconductor material layer is high.